Study On Calculation Method Of Acoustic And Vibration Response Of Large Capacity HTS Motor

High capacity HTS motor is gradually used in some fields because of its high efficiency and high power weight ratio.For ships,when the motor is running,the motor vibration and motor noise often accompany each other.The motor noise mainly includes electromagnetic noise,mechanical noise and ventilation noise.Electromagnetic noise is produced by electromagnetic vibration and is the main component of motor noise.This will not only endanger the physical and mental health of the personnel on board,but also reduce the acoustic stealth performance of the ship,which is fatal for combat ships.Taking a high-capacity HTS motor as the research object,the flow field of the cooling system in the scaled stator coil is calculated by Fluent,and its influence on the coil vibration characteristics is studied.The modal test and simulation analysis of the coil are also carried out to determine the reasonable and effective modeling method of the HTS motor.This method is used to model the stator core and the whole machine of the full-size HTS motor in Hypermesh.At the same time,the modal test and Simulation of the stator assembly are carried out to verify the correctness of material parameters.The electromechanical analogy analysis method is used to equivalent the stator yoke,pure iron core and stator-winding models to "single ring","double ring" and "three ring" models respectively,analyze and calculate their modes,and study the influence of constraints on their vibration characteristics.In addition,the electromagnetic force of HTS motor is calculated numerically,and it is loaded by ANSYS APDL command flow.The influence of different types of loads on its vibration response is analyzed.Based on the calculation results of vibration response,the acoustic simulation software LMS virtual.Lab The acoustic radiation characteristics of the motor are studied.The research contents completed in this paper are as follows:(1)Firstly,the three-dimensional geometric models of coil solid and coolant fluid are established,and then the finite element model is established.The dry mode of coil is calculated by using the coil solid model.On this basis,considering the fluid solid coupling effect of coolant fluid,the wet mode is calculated,the coolant flow field under different inlet velocity is analyzed,and the coil prestress mode under the pressure of flow field is calculated,The influence of different prestress on the vibration characteristics of coil is analyzed.(2)Based on the modeling method determined in content(1),the finite element model of scaled stator is established.In order to save the subsequent calculation time of full-size stator mode and vibration response,the finite element solid modeling,equivalent density method and additional mass method are studied to simulate the winding end,and the appropriate winding end simplification measures are determined according to the modal analysis results of scaled stator under the three modeling methods.In addition,the modal test of the scaled stator is carried out,and the test results are compared with the modal simulation results of the scaled stator based on the solid modeling of the winding end to verify the correctness of the material parameters.(3)Based on the modeling method and simplification measures determined above,the finite element models of the full-size stator and the whole machine are established,the influence of the constraint state on the vibration characteristics of the whole machine model is studied,and the modal simulation calculation and experimental test of the full-size stator assembly are carried out to further verify the correctness of the model integration method.The "single ring" equivalent model of stator yoke,the "double ring" equivalent model of pure iron core and the "three ring" equivalent model of stator winding are established by electromechanical analogy method,and a fast and accurate method for calculating the stator mode of HTS motor is obtained.(4)The electromagnetic force of the motor is calculated by Maxwell software simulation,and the named flow is compiled in ANSYS to load the electromagnetic force at the corresponding position in the form of point load.The transient response of the HTS motor is calculated,the vibration amplitude at different positions of the motor is analyzed,and the influence of Maxwell force and Lorentz force on the vibration response of the motor in different frequency bands is studied.(5)The closed boundary element model of HTS motor is established by Hypermesh.The vibration response data is transformed from time domain to frequency domain and mapped to the boundary element model.The radiated noise of motor structure is calculated by direct boundary element method.The magnitude of radiated noise at different field points and its distribution in different frequency bands are analyzed and studied.